Apparatus for grinding wood.



I. A. WALDRON. APPARATUS- FOR GRINDING WOOD APPLICATION FILED MAY 14, 1909.

Patented Sept. 30, 1913.

6 sums-15mm 1.

WITNESSES:

*5 INVENTOR BY MMW ATTORNEYS P. Ar WALDRON.

APPARATUS FOR GRINDING WOOD.

urmou'm! nun nu 14, 1909.

Patented Sept. 30, 1913.

" e sums-51mm: 2.

| VENTOR TTORNEYS WITNESSES: J' V P. A. WALDRON. APPARATUS FOR GRINDING WOOD.

APPLICATION FILED HAY 14,'1909.

Patented Sept. 30, 1913.

6 SHEETS-SHEET 3.

A INVENTOR WITNESSES 1 ATTO NEYS F. A. WALDRON. APPARATUS'FOR GRINDING WOOD.

Patnted Sept. 30,1913.

nrmommn FILED an 14, 1909.

a SHEETS-SHEET 4.

WITNESSES:

P. A WALDRON.

APPAILA'IUS FOR GRINDING WOOD.

APPLIUATION FILLED MAY 14, 1909.

1,074,144, Patepted s t.30,1913.

6 SKEETS-SHEEI 5.

WITNESSES: V INVENTOR BY W 41,, a W

. ATTORNE S P. A. WALDRON. APPARATUS FOR unmuING WOOD.

APPLICATION FILED HAY14, 1909.

Patented Sept. 30, 1913.

a SHEETS-BEBE! cl WITN ESSI I S:

FREDERICK A. WALDRON, or PLAINFIELD, new JERSEY.

APPARATUQ FOR GRINDING WOOD.-

Specification of Letters Patent.

Application filed May 14, 1909. Serial No. 496,015.

T 0 all whom it may concern:

Be it known that I, FREDERICK A. WAL- "DnoN, a citizen of the United States, residing at Plainfield, in the county of Union 5 and State of New Jersey, have invented certain new and useful Improvements in Apparatus for Grinding Wood, of which the following is afull, clear, and exact descriptlon.

This invention relates to Wood-grinding apparatus for use in the; manufacture of wood pulp, in which the wood is-disintegrated by means of a revolving element of stone or other suitable abrasive material.

Stated generally, the object of the invention is to provide improved apparatus for the purpose capable of operating at high efliciency, with means for effective control of the various operations performed by the machine.

To this and other'ends the invention consists in the novel. features of construction and combinations of parts hereinafter described and more particularly set forth in the appended claims.

The nature of the invention will be read ily understood from a more or less detailed description of the preferred embodiment in connection with the annexed drawings in so which the same is illustrated.

In the drawings, Figure 1 is aplan view of the apparatus, omitting the mechanism at one end of the main shaft for effecting the axial oscillation of the stone or rotating rinding... element. Fig. 2 is a section on no II-II of Fig. 1, looking in the direction of the arrows. Fig. 3 is a side View of the apparatus, viewed from the top of Fig; 1. Fig. 4; is a section on line IV-IV of Fig. 1, looking in the direction of the arrows. Fig. 5 is a horizontal section, taken on the plane passing through the axis of the stone. Fig. 6 is a detail sectional View of the valve which controls the fluid-pressure cvlinder employed in connection with a suitable governor for braking the rotating grinding element. Fig. 7 is a detail sectional view showing the driving and controlling mechanism for the revoluble carrier b which char es of wood re conveyed to the magazines in which the wood is held against the grinding element. Fig. 8 isa detail sectional view, somewhat dia- 'rammatic in character, showing the chute in which the lengths of sticks of wood are of wood from the chute, one of the station-- ary shelves to which the charge is delivered from the carrier, and one of the magazines, receiving the wood from the shelf. Fig. 9 1s a diagrammatic View illustrating the signahng system employed for indicating to the operator or attendant the approaching exhaustion of the charges in the magazines.

The grinding stone 1, (see Fig. 5) in the form of a short cylinder, is fixed to the main shaft 2, connected to a suitable motor 3 (Fig. 1) through the instrumentality of coupling mechanism st hereinafter described. The stone or grinding element is inclosed in a casing 5, the lower part of which, desig- Iatented Sept. 30, 1913.

nated by 6, serves as a receptacle to receive the disintegrated w0od.' VVater-jets (not magazines 7, 8, Fig. 2) for holding the pieces of wood during the grinding operation,

said magazines being of course open at their .inner ends to the interior of the casing so that the wood can be brought into contact with the stone. One of the magazines is located above the horizontal plane passing through the axis of the stone, and the other is below the said plane, while on the opposite side of the casing are two similar maga- Zines, 7, 8 diametrically opposite the magazines 7 and 8', respectively. At their outer ends the magazines are provided with followers 9, movable radially with respect to the grinding element 1 and actuated by fluid-pressure cylinders or ramslO, 11, 10*, and 11, said cylinders being associated withthe magazines 7, 8, 7 and 8*, respectively.- These followers serve .topress the charges of wood against the stone, as shown in Fig. 2; and it willbe seen that'the pressure exerted by each actuating pressure-cylinder or ram is opposed, exactly or approximately diametrically, to that of acylinder on the other side of the stone. The pressures being thus balanced, as it were, in all directions, the strain which would otherwise be very great on the main shaft and its bearings is substantially eliminated and the wear thereon largely reduced.

' At one side the magazines are provided with radially sliding doors or closures 12,

operated by fluid-pressure cylinders or rams 13,- 14, 13, 14, associated'with rams 10, ll, 10 and 11", respectively, so that when a ram retracts the follower to which it is connected,

the associated ram will retract the magazine closure for the admisslon of a fresh charge of wood lnto the magazine. For this purpose the rams 10, 13, for example, are connectcd'with the same pair of fluid-pressure supply pipes 15, 16, controlled by a. threeway valve 17 in the pressure distributing f pipe 18. Rams and 13 are connected to the same pair of supply pipes 15, 16, so as to operate in unison with the rams diametrically opposite. Similarly rams 11 and 14 are connected to supply pipes 19,20, to which rams 11 and 14? are also connected, under the control of a valve 21 in the main supply pipe 18. It will therefore be seen that none ofthe rams mentioned can be operated except in unison with the ram with which it is connected on the same side of the grinding element and in unison with the associated pair on the opposite side.

The pressure fluid, for example water or compressed air, is supplied to the distributing pipe 18 by a supply pipe 18" leading from a compressor or pressure tank, not shown, the flow of the fluid to the valves 17 and 21 being controlled simultaneously by a valve 18'. The exhaust from the rams is discharged by way of pipes 18, 18, connected to valves 17 and 21. Since the construction and operation of fluid-pressure control systems of the type thus outlined, are well understood, no further description of the same is necessary.

Alongside of each magazine, opposite the door or closure thereof, is one of a series of stationary receptacles or shelves 22, said shelves being mounted on a supporting member 23 through which the-shaft 2 passes. The construction of each shelf,.and its arrangement with respect to the adjacent magazine is shown more clearly in Fig. 8, in

which it'will also be seen that the shelf or receptacle is open at both sides, so that a charge of wood may be introduced through one side and discharged through the other into the magazine. These shelves constitute storage receptacles in which charges of wood are kept preparatory to introduction into the magazines. 1,

Alongside of the shelves is a series of revolving chambers 24: mounted on radial arms 25 connected at their inner ends to a hub 26 which is rotatably supported by the shaft 2. The hub has a worm gear 27 engaged by a worm 28 fixed on a vertical shaft 29 (see Fig. 7) which carriesoppositely dis- .posed bevel gears 30, 31 rotatably mounted thereon. These two gears are in constant mesh with a bevel gear 32 on a horizontal shaft driven by the motor through the in strumcntality of any suitable connecting mechanism, not shown. Mounted to slide on the vertical shaft 29 but to rotate there with is a clutch member 3?), having its ends coned and adapted to fit correspondingly formed seats in the bevel gears 30, 31. The clutch member is reciprocated on the shaft 29 by a hand lever 34, by which the said member may be shifted to reverse the direction of i'otat-ion of the revoluble carrier, or I to disconnect the same from the source of power, as desired. It will now be seen that the carrier can be rotated under the control of the operator to bring anyone of its re ceptacles opposite any one of the storage shelves".

Outside of the revoluble carrier, and in alinement with one of the magazines, say magazine 8, is a chamber 35, at .the bottom of. an inclined chute 35 down which the pieces of wood are passed. At the outer end of this chamber is a sliding gate 36, and in the chute, at a distance from said gate equal to the length of the chamber 35, is a second gate 37' The two gates are connected to opposite ends of a pair of centrally ful- 'crumed levers 38 operated by a hand lever 39 or other suitable meansso that when one gate is closed the other will be opened, and vice versa. At its upper end the chute has a lateral prolongation along which the pieces of wood, cut to proper length, are passed in any convenient manner.

, At the side of the feed chamber 35 is a plunger head 41, actuated by a fluid-pressure ram 42 controlled by a suitable valve, not shown, in the pipes 44 by which the pressure fluid is conveyed to and from the ram. Opposite each of the other stationary shelves and magazines is a similar apparatus, one of the rams being shownat 45.

he operation of the machine so far as described will now be readily understood.

The pieces of wood to be disintegrated are passed down the chute 35 gate 87 being raised and gate 36 closed. When the space betweenthe two gates is full the operator, on the platform 102 at the top of the machine, with the various controlling levers and valves in easyreach, reverses the gates,

whereupon the ood between the two passes into the chamber 35. The ram 42 is now operated to advance the plunger 41, thereby shoving the charge of wood from the chamber 35 into one of the carrying or distributing chambers 24. The operations just described are now repeated, the second actuation of ram 42 serving to push the second charge into the distributing chamber and ahead of it the first charge into the storage receptacle or shelf. The third charge then pushes the first into magazine 8, and the distributing chamber is thus left with a charge m it. The series of distributing chambers is now revolved step by step past the loading chamber 35 until all are filled, after which the ejecting rams opposite the other magazines are operated. The ejecting ram 45 has a long stroke, sufii'cient not only to carry the charge out of the distributing chamber but also to carry it across the stationary storage shelf and into the magazine.

UThe e ecting rams opposite the magazines 7 and 8 are of similar character, and hence the three magazines 7, 7* and 8 can be charged simultaneously or singly, as desired.

' 'Atone or more edges of each storage chamher-22 and distributing" chamber 24 are knives 46, 46"; (Fig. 8) so that'if for any "reason the wood, in being introduced into the chamber, should stick or catch on the edge the knife would simply take off a shavj 'ing and=allow the piece of wood to continue in its .movement. The four magazines being loaded the rams. 10, 11, 10 and 11, (whichjserve to press the wood against the grinding element and which for that reason y be conveniently termed the pressure rams), are started and the wood in the The fibers thus ground off the wood collect in the receptacle 6, being washed oil" the stone by suitable water jets, not'shown, from which receptacle the stock is discharged through the bottom. In the meantime the operator refills the empty distributing chambers in the revoluble carrier and sees that the storage shelves are kept filled, so that as soon as a pair of magazines is exhausted the same may be promptly'recharged. In this way the operator is able to keep the machine running at its full capacity at all times.

If for any reason an exhausted magazine should not be refilled promptly the stone would speed up or even race, and to prevent such a result suitable braking means are provided. 'A band brake, or other mechanism, may be employed for the purpose, but such method involves the waste of more or less power, and I thereforeprefer to brake the grinding element, when necessary, by applying to it an auxiliary charge of wood so that the power which would otherwise be wasted'can be utilized in making pulp. For this purpose an auxiliary or braking magazine 48 (Fi 2) is provided, similar to the others, an located at thetop'of the casing 5, preferably midway between the two upper magazines 7 and 8. Alongside of this auxiliary magazine is a storage shelf 22*, which is stored with wood by means of the revoluble distributer' inthe manner already described, and the magazine has a radially sliding closure 49 operated by a ram 50. The magazine also has a pressure.

ram 51, operating like the other pressure rams, by which the wood is pressed against the grinding element. This ram 51, which for convenience may be termed the braking ram, and ram 50, are connected to fluid pressure pipes 52, 53, and are controlled by a valve 54, so that the operator can at any time throw the two rams into action and cause the wood in the braking magazine to be pressed against the grinding element,

thereby braking the latterwithout wastingpower.

Provision is also made for applying the brake automatically whenever the speed of the stone exceeds a predetermined limit. For this purpose a centrifugal governor 55 (Figs. 3 and 4) is employed, driven bya belt 56 from a pulley 57 on the main shaft 2. This overn-or actuates a floatin lever 58 pivotedat the lower end of a link 59 -which is itself pivoted to the end of a lever 60, the latter being fulcrumed at. 61 and connected to the piston 62 of ram 51. Since the latter ram is normally idle, with its piston retracted, it will be seen that the fulcrum of lever 58 is in efiect fixed. Hence the outward movement of the governor balls will raise the connected end of lever 58 and depress the other end, which is connected with the piston 63 of a valve 64 COI1tI'0llingi I the supply of pressure fluid to the braking ram. The construction of this valve is illustrated in detail in Fig. 6, in which it will be seen that the said piston has a vertical passage 65 through it, and a circumferential passage or channel 66. At .one side-'thevalve cylinder 67, in which the piston works, is connected by pipes 68, 69, to the pipes 52, 53, which latter, it will be remembered, connect the braking ram with the'fluid-pressure ated valve 5%. The parts described are so proportioned and arranged that when the braking mechanism is idle, with the piston of the braking ram retracted to its outermost position, the piston 63 will stand as shown in Fig. 6, with the pipes 68, 69, closed by the flanges which bound the circumferential passage 66. On the other hand, pipes 70, 71, connected with the cylinder, are so located that the former is open at all times to the said circumferential passage while the latter is at the bottom of the cylinder and-hence is closed only when the piston is in its lowermost position. Pipe 71 being connected to the source of fluid pressure (in any convenient manner, not shown) it will be seen that if the grinding element should speed up and thereby cause the governor balls to fly out and depress the piston 63 the pipe 68 will be uncovered and the pressure-fluid from pipe 71 will flow up through passage 65 into pipe 68 and thence torams 50 and 51, While the exhaust from said rams will flow out through pipe 53, 69, circumferential exhaust passage 66, and-pipe 70 to the atmosphere. The ram 51 will therefore press the. wood in the braking supply pipe 18 through the manually opermagazine against the stone. When the speed of the latter is diminished to the normal, the, collapse of the governor balls restores the governor valve to its normal condition as in Fig. 6, thereby shutting ofl' the fluid,- pressure from rain 51 and causing the wood in the braking magazine to bear only by its own weight against the grinding, element.

This restoration is aided, as will be readily seen, by the slight lifting of the lever 58 by the falling of piston 62, through the 'instruinentality of lever 60 and link 59.

v purpose the outer ends of the pistons of the contact 76, thereby establishing pressure rams are connectecb by cords 72 (Fig. 3) to drums 73-on which the cords are wound, in' such manner, for example as shown, that as the piston advances in the operation of pressing the wood against the grinding element the drum will be revolved. These drumsare geared to pointers 74 in front of dials 75, and each pointer and dial are connected with their own signaling devices, as shown in detail inFig. 9. As the pressure-piston advances it revolves the pointer, and as the charge in the magazine approaches exhaustion the pointer strikes a an electric circuit through the pointer, w1re 77 (connected to the pointer), battery :78, bell 79, and contact 76,and thereby causing a mo-- mentary ringing-of the bell. The operator is thus notified of the condition of the charge. If, however, th'e signal should fail to attract his attention, the pointer, moving on to the next contact, 80, a circuit will .be established through the pointer, wire 77, battery 78, wire 81, lectromagnet 82, and contact 80. The' magnet, thus energized draws its armature 83 over and releases the sprin contact 84 which is normally held Separate from the cooperating contact ,85

by the hook on the armature in the manner shown. Release of contact 84 permits the same to rise and impinge on the contact 85, .thereby establishin a circuit through wire 86, battery'.7 8, bell 9, wire 87, and contacts 84 and 85. The bell. is thus again operated, andv continues to, ring, irrespectiveof the pointer or the magnet, until theope rator.

breaks the circuit, last traced, by pulling cord 88 and therebyseparating the contacts. The magnet 82, being already deenergized by the pointer moving ofi" of contact 80, allowed its armature to be retracted by spring 89, and hence the contact 84, in its downward movement under the pull of cord '88, will be reengaged with the armature hook, thus restoring the system to its initial condition.

The friction of the wood on the grinding element will usually result in wearing one or 11110113 grooves in thestone, thereby impairing theefiicienoy of the machine. This drawback is obviated in the present apparatus by giving the axial movement of osci lation, 0 that in the long run all parts of the face t ereof will be worn equally and the output of the machine thereby kept at the maximum. For this purpose the shaft 2 is provided with a worm 9O, feathered thereon and meshing with a.

worm gear 91. The latter drives a crank disk 92 connected to a link 93 which is pivoted to the end of a lever 94. This lever is fulcrumed at its other end and at an intermediate point is rovidedwith a pin 95 engaging a circum erential groove on collar 96 fastto shaft 2. It will therefore be seen that the worm 90, held against axial movement between two thrust bearings 97, rotates the gear and crank-disk, thereby oscillating the lever 94 and effecting a corresponding axial movement of the shaft 2 and grinding element 1. To permit such movement of the shaft 1, it is connected to themotor by means of a coupling or connecting element 4, shown in detail in Fig. 5. The shaft carries a disk 98, provided with a plurality of axially extending fingers 99, which project into a circular groove in the face of a memher or disk 100 on the motor shaft, in which groove the said fingers engage antifrict-ion rollers 101 mounted radially in the groove. It will therefore be evident that the shaft 2 will be rotated by the revolving disk 100 but that the fingers 99 are capable of axial movement with respect to the rollers 101 without disengagement therefrom.

'On top of the casing 5 is a platform 102, surrounded'hy a railing 103. At the back of the platform is a vertical panel or board 104, on which the indicators 7 5 are mounted, while "in front of the panel are the controlling valves 17, 18", 21, 54, and the-lever 39,

all within easy reach of the operator standing on the platform.

What I' claim is:

1. In an apparatus for grinding wood, in combination, a rotary grinding element, a plurality of pairs of magazines for holding charges of wood arranged on diametrically oppositesides of the grinding element, and fluid-pressure mechanism for simultaneously pressing the'wood in all the pairs of magazines against the rotary grinding element, whereby the pressure on the grinding element at one side is opposed by corresponding pressure on the opposite side 'upon the simultaneous operation of the magazines of each pair.

2. In an apparatus for combination, a rotary grindin plurality of magazines for hol in'g charges of wood arranged in diametrically opposite inding wood, in

rinding element an element, a

pairs, fluid-pressure mechanism for pressing the wood in all the pairs of magazines against the grinding element, and controlling devices controlling the magazines of all of said pairs simultaneously when the magazines of each pair are operated in unison.

3. In an apparatus for grinding wood, in

combination, a rotary grinding element,

magazines arranged in diametrically opposite pairs for holding charges of wood, fluid pressure means for pressing the wood in the .magazines upon the grinding element, controlling devices adapted to simultaneously operate all the pairs of magazines whereby upon the simultaneous operation of one pair of magazines the pressure upon the grinding element is equalized, and means for retracting the wood pressing devicesin any of the; opposite pairs of magazines.

4. In an apparatus for grinding wood, in combination, a rotary grinding element, a magazine for holding a charge of wood, a magazine diametrically opposite the first, closuresfor the said magazines, fluid pressure rams for pressing the. wood in the magazines against the grinding element, fluid pressure rams for operating the magazine closures and controlling means whereby the said closure operating and pressing rams may be operated in unison.

5. In an apparatus for grinding wood, in combination, a rotary grinding element, means for holding wood in contact with the grinding element, a breaking magazine for holding an auxiliary charge of wood, and

means dependent for operation upon the speed of the grindin element for pressing t e wood in the braliingmagazine against the grinding element.

6. In an apparatus for grinding wood, in combination, a rotary grinding element, means for holding wood in contact with the lgrinding element, a braking magazine for lding an auxiliary charge of wood, mechanism for pressing the wood in the brakingl magazine against the grinding element, an

automatic governor means connected with said rotary grinding element for controlling said mechanism.

7. In an apparatus for grinding wood, in combination, a rotary grinding element, means for holding wood in contact with the grinding element, a braking magazine for holding an auxiliary charge of wood, an automatic mechanism for pressing the wood in the braking magazine against the grinding element, and pressure devices for controlling said mechanism dependent for operat-ion upon the speed of the grinding element.

8. In an apparatus for grinding wood, in combination, a rotary grinding element, a plurality of magazines for holding charges of wood in contact with the grinding element, a revoluble carrier independent of the devices for holding the wood in contactjwith of wood, storage receptacles adjacent to the respective magazines, means for distributing wood to the storage receptacles, and means independent of the ressing devices for discharging the wood rom the said receptacles into the magazines;

10. In an apparatus for grinding wood, in combination, a rotary grinding element, a plurality of magazines for holding charges of wood in contact with the grinding element, storage receptacles adjacent to the respective magazines, a revo-luble carrier for distributing wood to the storage receptacles, and means for loading the carrier.

11. In an apparatus for grinding wood, in combination, a rotary grinding element, a magazine 'for holding wood in contact with the grinding element, a closure for the magazine movable to permit the introduction of wood thereinto, mechanism for pressing the wood in the magazine against the grinding element, and closure-actuating means concoinitantly with the said pressing mechanism..

12. In an apparatus for grinding wood, in combination, a rotary grinding element, a magazine for holding wood in contact with the grinding element, a closure for the mag azine movable to permit the introduction of wood thereinto, fluidepressure mechanism for pressing the woo-d in said magazine against the grinding element, fluid-pressure mechanism for actuating the magazine closure, and means for supplying fluid under pressure to both said mechanisms simultaneously.

18. In an apparatus for grinding wood, in combination, a rotary grinding element, a

magazine for holding wood in contact with 110 the grinding element, a storage receptacle adjacent to the magazine, a revoluble carrier for conveying wood to the storage receptacle, means for dischargingwood from the carrier into the storage receptacle and thence 115 'into the magazine", and a movable element between the magazine and the storage receptacle'adapted to close the communication between the two.

14. In an apparatus for grinding wood, in no combination, a rotary grinding element, a magazine for holding a charge of wood in contact with the grindingelement, means for pressing the charge of wood against the grinding element, and a signaling system as- 125 sociated with the said pressing means for indicating the quantitative condition of the charge in the magazine, said system comprising a scale and pointer, means operatively connecting the same with the said pressing 130 means, to give usual indication of the condition of the charge, and means for giving an audible alarm when the charge approaches exhaustion.

15. In an apparatus for grinding wood, in

combination a rotary grinding element, a,

magazine for holding a charge of wood in contact with the grinding element, means for pressing the charge of wood against the giving a momentary alarm when the charge Correction in Letters Patent No. 1,074,144.

is approachimg exhaustionand a continuing alarm at a nearer approach to exhaustion.

16. In an apparatus for grinding wood, in combination, a rotary grinding element, a main driving member for said grinding element means for holding wood in contact with said grinding element, means for imparting to the rotary grinding element an axial" movement of oscillation, and an anti-friction coupling between said main driving element and said grinding element.

17. In an apparatus for grinding wood, in combination, a rotary grinding element, a shaft on which the same is rigidly mounted, means for oscillating the shaft axially, a motor for rotating the shaft, and an antifriction coupling connecting the motor and the shaft. and constructed to permit the oscillatory'movement of the latter.

18. In an apparatus for grinding wood, a rotary grinding element, a plurality of pairs of magazines for holding charges of wood, said pairs being located upon diametrically opposite sides of the grinding element, closures for the magazines, fluid pressure means for pressing the wood in the magazines I against the grinding element, fluid pressure casein the Patent Ofiice.

[sEAL] Signed and sealed this 14th day of October, l)., 1913.

means for operating the magazine closures and controlling devices for the fluid pressure means whereby the pressers ina pair of magazines may be operated in unison, said controlling means adapted to simultaneously operate the closures in the aforesaid pair of magazines. V

19. In an apparatus for grinding wood, in combination, a rotary grinding element, a plurality of pairs of magazines for holding charges of wood arranged on diametrically opposite sides of the grinding element and fluid pressure mechanism having a unitary cont-rolling device for simultaneously pressing the wood in all the pairs of the magazines against the-rotary grinding element whereby'upon the simultaneous operation of the magazines of one pair the pressure on .the grinding element at one side is opposed by a corresponding pressure on the opposite side.

20. In anapparatus for grinding wood, in

combination, a rotary grinding element,

magazines arranged in diametrically oppo site pairs for holding charges of wood, fluid pressure means for pressing the wood in the .65 magazines against the grinding element, and

a unitary controlling device for simultaneously pressing the wood in all the pairs of Y magazines against the grinding element whereby upon the simultaneous operation of the magazines of a pair the pressure upon said element is equalized.

In testlmony whereof I afiix my signature in the presence of two subscribing witnesses.

. FREDERICK A. WALDRON. Witnesses:

J. B. HAYWOOD, Q v M. LAWSON DYnn.

It ishereby certified that in Letters Patent No. 1,07 4,144, granted September30, I 1913, upon the application of F rederickA. Waldron, of Plainfield, New Jersey, for an improvement inApparatus for Grinding Wood, an error appears in the printed specification requiring correction as follows: Page 5, line 93, after, the word means insert the word operating} and that the said Letters Patent should be read with this correction therein that the same may'contormto the record of the RTEQRAZIER, Act'ing C'om-missionergf Patents.

' means, to give usual indication of the condition of the charge, and means for giving an audible alarm when the charge approaches exhaustion.

15. In an apparatus for grinding wood, in

combination a rotary grinding element, a,

magazine for holding a charge of wood in contact with the grinding element, means for pressing the charge of wood against the giving a momentary alarm when the charge Correction in Letters Patent No. 1,074,144.

is approachimg exhaustionand a continuing alarm at a nearer approach to exhaustion.

16. In an apparatus for grinding wood, in combination, a rotary grinding element, a main driving member for said grinding element means for holding wood in contact with said grinding element, means for imparting to the rotary grinding element an axial" movement of oscillation, and an anti-friction coupling between said main driving element and said grinding element.

17. In an apparatus for grinding wood, in combination, a rotary grinding element, a shaft on which the same is rigidly mounted, means for oscillating the shaft axially, a motor for rotating the shaft, and an antifriction coupling connecting the motor and the shaft. and constructed to permit the oscillatory'movement of the latter.

18. In an apparatus for grinding wood, a rotary grinding element, a plurality of pairs of magazines for holding charges of wood, said pairs being located upon diametrically opposite sides of the grinding element, closures for the magazines, fluid pressure means for pressing the wood in the magazines I against the grinding element, fluid pressure casein the Patent Ofiice.

[sEAL] Signed and sealed this 14th day of October, l)., 1913.

means for operating the magazine closures and controlling devices for the fluid pressure means whereby the pressers ina pair of magazines may be operated in unison, said controlling means adapted to simultaneously operate the closures in the aforesaid pair of magazines. V

19. In an apparatus for grinding wood, in combination, a rotary grinding element, a plurality of pairs of magazines for holding charges of wood arranged on diametrically opposite sides of the grinding element and fluid pressure mechanism having a unitary cont-rolling device for simultaneously pressing the wood in all the pairs of the magazines against the-rotary grinding element whereby'upon the simultaneous operation of the magazines of one pair the pressure on .the grinding element at one side is opposed by a corresponding pressure on the opposite side.

20. In anapparatus for grinding wood, in

combination, a rotary grinding element,

magazines arranged in diametrically oppo site pairs for holding charges of wood, fluid pressure means for pressing the wood in the .65 magazines against the grinding element, and

a unitary controlling device for simultaneously pressing the wood in all the pairs of Y magazines against the grinding element whereby upon the simultaneous operation of the magazines of a pair the pressure upon said element is equalized.

In testlmony whereof I afiix my signature in the presence of two subscribing witnesses.

. FREDERICK A. WALDRON. Witnesses:

J. B. HAYWOOD, Q v M. LAWSON DYnn.

It ishereby certified that in Letters Patent No. 1,07 4,144, granted September30, I 1913, upon the application of F rederickA. Waldron, of Plainfield, New Jersey, for an improvement inApparatus for Grinding Wood, an error appears in the printed specification requiring correction as follows: Page 5, line 93, after, the word means insert the word operating} and that the said Letters Patent should be read with this correction therein that the same may'contormto the record of the RTEQRAZIER, Act'ing C'om-missionergf Patents. 

